Bacterial flagellum

Yes on the atom, I believe there was a little more than that, but it was a long time ago. I think they spoke of the force which binds it together.
Either way the flagellum is to me facinating and worthy of being showed at a high school level, IMO.Please not dwell on the fact that I am upset about not learning about it ealrier. My fault for mentioning it.I never said complex either, you did.
Humans are way more complex than flagellum.Its the fact that it spins, and works like an electric motor. Is there in anything else in nature that can compare to that?Also the tail is not really connected, because it is spinning. Is there anything else in nature that has a part of itself not connected?

Thanks, I am going to try and read that, but it will take some time.

I think you're mistaken about that. The flagellum doesn't spin like the rotor of a motor. It whips about (hence the name "flagellum", from the latin for "whip") but doesn't actually rotate. It's more like a wisking action.It's not really like an electric motor. It's more like a whipping hair than anything else, as far as I know.

Remember that electricity plays a big part in every organism, it's not all that unusual. We are all part electric motor and infact, just as in the most modern airplanes, we ALL fly-by-wire.

---

Aslan is not a Tame Lion

Well there are many variations on just the bacterial flagellum Behe talks about, which itself shows evolution.This is the abstract for a paper describing the flagellum used by archaea
The archaeal flagellum: a different kind of prokaryotic motility structure.
This page links to a full paper which may be downloaded in pdf format
The archaeal flagellum: a unique motility structure.EvoWiki has an introduction to different sorts of flagella here
Flagella
which tells me that I missed the fact that eukaryotic bacteria have yet another sort of flagellum. It also notes that some bacteria use a different "engine" (using sodium ions instead of hydrogen ions).I'm not aware of any macroscopic structures that use the same mechanisms and I'm not sure that I would expect them - what works at the molecular level doesn't necessarily scale up well.

I believe it does indeed spin, at 20,000 to 30,000 rpms.
Its effecientcy is at almost 100% also, something we are not able to acheive with conventional electric motors.

Yes everything in nature uses electric pluses to send commands through the nervous systems.
But to spin a rotor is something completely different.

OH yea I forgot this one too, it does spin at 20,000-30,000 rpms.
And can stop in a quarter of a turn, then spin the other way.
So it even reverses its self, adding to the complexity.Like having a reversing curcut in an eletric speed control.

You believe wrong, according to my wife's cell-molec textbook (World of the Cell 4th Edition, Becker, Kliensmith, and Hardin). Bacterial flagella beat back and forth. They don't rotate in place like the shaft of an electric motor.Nothing in nature rotates freely, not even flagella.

Dear Crashfrog,I'm not sure that your wife's textbook is in the right here. I just did a quick look for 'bacterial flagella' on the books section of the NCBI website, and the articles in the texts there all seem to agree that the flagella is a rotatory system with the rotation of the MS protein ring to which the flagella is attached being driven by a proton gradient, this is a precis of material from Stryer, Biochemistry, fifth edition.Since the ability to change the direction of rotation from counterclockwise to clockwise is neccessary for the tumbling period of motion I think a rotatory system has to be in action. It may be that your wife's textbook is more recent, perhaps you could find a primary source reference from it for this fact?TTFN,WK

Check the book again; if that is really what it says, then it is wrong. There are several different kinds of flagella in nature. The three major divisions are bacterial, archaeal (another sort-of bacteria) and eukaryotic (not bacteria, but cells with a nucleus).It is the eucaryotic flagella that beat; but both forms of bacterial flagella do indeed truly rotate.More information is available from wikipedia, and is also available in a number of discussions of flagella on-line.Cheers -- Sylas

I'm looking right at it; it has pictures and stuff, and it's pretty clear.Maybe we're miscommunicating or something. It seems to me that the Rat is saying that the bacterial flagellum free rotates within its socket, like the shaft of a motor, around the long axis of the flagellum.The textbook says that it beats back and forth, or whips around in a circular motion, but doesn't actually spin. The flagellum whips around like if you were to grab a garden hose in one hand and move your hand up and down and left and right, in a circle - the hose whips around, kind of in a helix, but doesn't actually spin freely of your hand.Like I said, the textbook is pretty clear about that. I don't think I'm misunderstanding it. From what I'm reading, bacterial flagella don't rotate in a socket like the shaft of a motor, they whip around like whips.

Except of course for those things that don't have nervous systems. Which is most living things, really. And the 'electric pulses' are not the same as electrons within electric wires. What they actually are is ions being moved back and forth across membranes. That sort of thing is rather more widespread.DT

According to the Wikipedia entry the "motor" can manage 6-17,000 rpm but usually only does 100-200 rpm when the whip is actually attached.The efficiency figure appears to refer to the "motor" alone - Page not found | American Institute of Physics makes that claim. But the efficiency of the flagellum as a whole is much lower - according to this page 9.4.2.4 the efficiency of the flagellum to actually propel the bacteria is at best in the range 10-28% - nowhere near 100%. In fact it may well be as low as 1% as mentioned in the previous link and in this one:
http://brodylab.eng.uci.edu/...rody/reynolds/lowpurcell.html

Hmmm, interesting. This reliable-looking site says:

quote:

---

Flagella consist of a hollow, rigid cylinder composed of a protein called flagellin, which forms a filament anchored to the cell by a curved structure called the hook, which is attached to the basal body.

---

This certainly makes it sound more like Crash is suggesting. This site, I thought, confirmed it:

quote:

---

Flagella can be thought of as little semi-rigid whips that are free at one end and attached to a cell at the other. [...] The hook and basal body of the flagella attach it to the cell.

---

... but goes on to say

quote:

---

The flagellum is a rigid structure and rotates like a propeller. Rings in the basal body rotate relative to each other causing the flagella to turn.

---

So now I'm even more confused. It's clear that it acts like a whip in its motion, but does it also rotate within its ‘socket’ too?DT